The invention relates to a microtome.
DE 31 44 120 A1 has disclosed a traversing microtome which contains a base and a carriage which can be moved along slide rails. The cutting blade is in this case fixed immovably to the base, while the specimen holder is arranged on the carriage. In order to make the cut, the carriage is moved manually along its guide on the base.
However, traversing microtomes are also known in which the cutting blade is mounted on the carriage and the specimen holder is mounted in a fixed position on the base.
In both types of traversing microtome, the specimen is cut by way of a relative movement between the cutting blade and the object.
Another type of microtome is known from DE 195 31 524 C1. The rotary microtome described in this document has an object carriage on which there is an object holder for the specimen which is to be cut. The object holder is moved up and down on the rotary microtome in a vertical path. During this movement, the specimen is guided past a blade which is arranged in a fixed position on the rotary microtome.
In this case too, the specimen is cut by way of a relative movement between the cutting blade and the object. In both types of known microtome, it is necessary to return the object or the cutting blade to the starting position after a cutting operation has taken place. During this return movement, it is imperative that the cutting blade does not collide with the specimen if clean specimen cuts are to be produced. In both cases, this is achieved by the cutting blade or the specimen being retracted a certain amount by means of a feed device, so that the moving component can be moved past the fixed component. In the event of a further cutting operation, the specimen or the cutting blade is advanced again by this certain amount plus the cut thickness set.
Both types of microtome have proven themselves in practice. The need for a return movement to a starting position after a cutting operation has taken place means that microtomes of this nature are unable to achieve rapid cutting sequences. In addition, these oscillating movements result in considerable forces during the acceleration or deceleration of the moving components, and these oscillations have to be compensated for, entailing a high level of mechanical outlay. Otherwise, there is a risk of vibrations being transmitted to the microtome, resulting in unusable thin-cut sections.
The document "Leica SP 1600--Saw Microtome, Instruction Manual, V0.0 English--11/86, from Leica Instruments GmbH" has disclosed a saw microtome for cutting very hard objects, such as bones, ceramic, etc. As its cutting blade, the saw microtome has a diamond-tipped annular saw which rotates at 600 rpm. The object to be cut is arranged, together with the object holder, on a rotationally movable arm. The arm is pivoted extremely slowly toward the annular saw in order to carry out a sawing cut. Following the sawing cut, the arm has to be moved back again. This microtome does not allow continuous cutting or the cutting of tissue samples.
DE 26 40 966 A1 and JP 63-241442 A have disclosed cutting devices in which a disk-like cutting blade is driven by a motor. Arrangement [sic] of this nature are used to produce thin-cut sections of very hard materials, such as bone.
DE-C 263 871 has disclosed a microtome with a fixed blade and a rotating object holder. The cutting blade is arranged in a blade holder which is fed onto the object holder using mechanical means for setting the cut thickness. A simple crank handle is used to drive the microtome described.
AT 172 605 and U.S. Pat. No. 3,191,477 have each disclosed a microtome with a rotatably mounted disk. A specimen holder is arranged on the end side of the disk, so that the axis of rotation of the disk is approximately perpendicular to the cutting plane. In this arrangement, the object is guided past the cutting blade along an orbital path, so that the cut section acquires a cylindrical profile. However, in many cases this cylindrical profile cannot be used during a subsequent microscopic examination, since the cut section has to be placed flat beneath the microscope.
DD 5 620 has disclosed a motor-driven, revolving blade carrier in which the object holder is advanced by means of an eccentric disk and a lever which acts thereon. This arrangement provides for a parallel arrangement of object and blade during the cutting operation. However, the object is advanced not by means of a linear component but rather using a lever and an eccentric disk.
U.S. Pat. No. 3,884,563 describes a microtome with a motor-driven, revolving blade carrier in which the object holder is advanced by means of a carriage. The microtome also has a cryostat and a film camera which is used to film the specimen during the cutting operation. In this microtome, the cut sections are not examined further, but rather are disposed of via a collection container.
U.S. Pat. No. 2,753,761 and GB-C 654 123 describe disk microtomes in which the object holder is arranged on a disk and the blade holder is arranged fixedly on the microtome. In this case, the cutting advance takes place by way of a parallel displacement of the disk with respect to the base, using a thermocouple and a spindle, or by way of a parallel displacement of the blade holder on the base. There is no provision in these documents for motor-controlled feed.
U.S. Pat. No. 3,902,390 has disclosed a pocket microtome in which the cutting blade is arranged on a rotationally moveable arm and can be manually preloaded by means of a spring. This microtome is designed for portable use and is unsuitable for carrying out series of cuts.